Aircraft propeller



' Dec. 28, 1937. w. w. BRADFORD, JR 2,103,243

I AIRCRAFT PROPELLER Original Filed April 16, 1932 Patented Dec. 28, 1937 UNITED" STATES AIRCRAFT PROPELLER William W. Bradford, Jr.,

Bel Air, Md., assignor to Howard B. Hyle, Catonsvill'e, Md, Eldridge Hood Young, Baltimore, Md., and-- Stanley Turner Holmes, Harford County, Md;

Substitute for application Serial No. 605,741,

April 16, 1932. This application- 1936, Serial No. 101,833

17 Claims.

This application is a'substitute for my application Serial No. 605,741, filed April 16, 1932 which became abandonedon January 20, 1934.

This invention relates to a propeller for aircraft. In my co-pending application Serial No.

98,772, filed August 31, 1936, I have shown a propellerin the operation of which air is drawn into a-circular revolving head and is thrown out at high velocity through restricted openings atits periphery in a direction to carry it past an annular plate which projects radially outward beyond the openings but is out of line with the openings. Anannularpocket-is formed between this plate and the head, and the air stream passing over this pocket causes a partial Vacuum to be created in said pocket and over'the annular plate and atmospheric pressure causes the airstream to be deflected toward the plate. The air stream and centrifugal force co-act to remove the pressure from the forward side of the plate and atmospheric pressure on the opposite side of the plate and head tends to move the propeller forward.

In the present invention, instead of throwing the air'radially outward over an annular-plate,

5 -I provide a head'which may be attached to a propeller shaft and a plurality-of wings equally spaced apart circumferentially of the head, each wing projecting laterally outward from the head and having a plurality of I funnels for catching 5; the air as thehead rotates. These funnels, which re on the forward part of each wing and extend transversely thereof, have their outlet ends spaced-'frorn the base plate of the wing by a wall which forms a pocket between said ends and said plate: The air issuing at high velocity from these funnels passesover the pocket and is deflected by atmospheric pressure toward the rear part of the-plate and the air flowing over and past the plate and pocket removes the pressure 40' from one side of the plate and atmospheric pressure on the, opposite side tends to lift the propeller or force it forward;

In the accompanying drawing, Fig. '1 is a front end view of the propeller; Fig. 2 is a side elevation of the same; and V Fig; 3 is a section through one of the propeller wings,-taken on the line 3-3 of Fig. 1. For convenience in the use of terms, the propeller will be described as a lifting propeller, al-

7 though it is intended to be used either for lifting or-pulling. Referring to the drawing, it indicates ahollo'whead, to the base of which is attached a coupling 1) by which the headmay be attached to the end of a propeller shaft. The form of the h'ead mayvary, but preferably'it is conical, its

September 21,

outer surface sloping at anangle of approximately45 to its axis, as Shown in the drawing.

A plurality of wings c, evenlyspaced apart circumferentially of the head, project laterally outward from its base, each wing being inclined forwardly with respect to the direction in which thepropeller rotates, which direction is indicated by the arrow in Fig. 1. Each wing-com prises an oblong base plate l which extends laterally-outward from the'head,flush with'its base,

the rear part l of'the plate curving slightly downward, as shown in Fig. 3. Upon the base plate is arranged a plate 2, one edge of which iswelded to the forward or leading edge of the plate I; the meeting edges of the plates "being indicated at 3. and rearwardly from its forward edge and the rearpart? of the plate extends-substantially parallel-with th'e 'plate'l and is supportedby a fiatstrip 4 which forms a wallextending from end to end of the wing. The part 2?? of the plate 2-projects rearwardly a short distance beyond the wall- 4, as shown, thereby forming a pocket 5" The plate" 2" inclines upwardly between the plates at the rear of the wall. The '1 several plates and the wall t extend to the surthereto.

plate I is secured to the upper edges of these partitions. The partitionsare approximately concentric with the axis of the head. An end plate 8 extends across the outer end of each wing, the 3 forward part of this plate fitting againstthe ends of the base, intermediate and upper wing plates I, 2 and l, and the wall:4, and the rear part 3 of the plate 8 curves slightly outward:

and extends to the rear edge of the ,base plate,

the top edge of said rear part sloping or curving.

from the upper plate to the base plate, as shown.

The partitions and the intermediate and upper plates form a series of funnels 0', c c and 0 the larger" ends of which are at" the forward or leading edge of the'wing, while the'smallerends of the funnels projectover'the supportingstrip whichis aboutmidway between the front and rear edges of the base plate I. Each wing is preferably inclined slightly downwardly from the 1 base of the head, as shown in Fig. 2 of the;

drawing.

In operation, the propeller is rotated very rapidly'and the air which enters the funnels through their larger ends is highly. compressed. in the funnels and issues withhigh velocityfrom their smaller ends; Asthe" air issues from the'funnls, it is drawn downwardly toward the rear half of the base plate and flows over and past the rear edge-of the plate. In issuing from the hoppers, the air jets are also carried outwardly over the base plate by centrifugal force, so that the air issuing from the jets flows downwardly toward the rear part of the base plate and diagonally over it, passing off at its rear edge.

My theory of the operation of the propeller is that the high velocity air streams passing over the pocket 5 cause a partial vacuum to be created in said pocket and atmospheric pressure causes the streams to be deflected downwardly over and past the rear half of the base plate, the air streams acting to remove the air pressure from the upper side of the plate, thereby creating a difference in atmospheric pressure on opposite sides of the plate, which tends to lift the wing. I do not, however, wish to confine myself to any particular theory of operation.

What I claim is:

1. An air-craft propeller comprising a head adapted for connection to a propeller shaft and a plurality of wings spaced apart circumferentially of the head, each wing comprising an oblong base and top plates extending laterally from said head, the top plate being of less width than the base plate and extending over the forward part of the latter, and spaced partitions forming transverse air passageways between said plates, the discharge ends of said passageways being spaced from the base plate.

2. An air-craft propeller comprising a head adapted for connection to a propeller shaft and a plurality of wings spaced apart circumferentially of the head, each wing comprising an oblong base plate extending laterally from said head, and funnels on the upper side of the plate having their larger ends facing the direction of motion of the wing and their smaller ends arranged to discharge air rearwardly above the rear portion of the plate.

3. An air-craft propeller comprising a head adapted for connection to a propeller shaft and a plurality of wings spaced apart circumferentially of the head, each wing comprising an oblong base plate extending laterally from said head, and funnels on the upper side of the plate having their larger ends facing the direction of motion of the wing and their smaller ends arranged to discharge air rearwardly above the rear portion of the plate, the smaller ends of the funnels being spaced from the plate.

4. An air-craft propeller comprising a head adapted for connection to a propeller shaft and a plurality of wings spaced apart circumferentially of the head, each wing comprising an 0blong base plate extending laterally from said head, funnels on the upper side of the plate having their larger ends facing the direction of motion of the wing and their smaller ends arranged to discharge air rearwardly above the rear portion of the plate, and a wall between the plates adjacent the discharge ends of the funnels.

5. An air-craft propeller comprising a head adapted for connection to a propeller shaft and a plurality of wings spaced apart circumferentially of the head, each wing comprising an oblong base plate extending laterally from said head, and funnels on the upper side of the plate having their larger ends facing the direction of motion of the wing and their smaller ends arranged to discharge air rearwardly above the rear portion of the plate, the upper walls of said funnels inclining from the forward ends rearwardly toward the plate.

6. An air-craft propeller comprising a head adapted for connection to a propeller shaft and a plurality of wings spaced apart circumferentially of the head, each wing comprising an oblong base plate extending laterally from said head, funnels on the upper side of the plate having their larger ends facingthe direction of motion of the wing and their smaller ends arranged to discharge air rearwardly above the rear portion of the plate, and a wall between the plate and funnels, located a short distance in advance of their discharge ends, forming a pocket between the funnels and plate.

7. An air-craft propeller comprising a headadapted for connection to a propeller shaft and a plurality of wings spaced apart circumferentially of the head, each wing comprising an oblong base plate extending laterally from said head and having its rear portion inclined downwardly, and funnels on the upper side of the plate having their larger ends facing the direction of motion of the wing and their smaller ends arranged to discharge air rearwardly above the rear portion of the plate.

8. An air-craft propeller comprising a head adapted for connection to a propeller shaft and a plurality of wings spaced apart circumferent-ially of the head, each wing comprising an 0blong base plate extending laterally from said head and having its rear portion inclined downwardly, funnels on the upper side of the plate having their larger ends facing the direction of motion of the wing and their smaller ends arranged to discharge air rearwardly above the rear portion of the plate, and a wall bet-ween the plate and funnels, located a short distance in advance of their discharge ends, forming a pocket between the funnels and plate.

9. An air-craft propeller comprising a head adapted for connection to a propeller shaft and a plurality of wings spaced apart circumferentially of the head, each wing comprising an oblong base plate extending laterally from said head, and funnels on the upper side of said plate extending transversely thereof, the mouths of said funnels being adjacent the forward edge of the plate and the discharge ends of the funnels being adjacent and spaced from the central portion of the plate.

10. An air-craft propeller comprising a head adapted for connection to a propeller shaft and a plurality of wings spaced apart circumferentially of the head, each wing comprising an oblong base plate extending laterally from said head, funnels on the upper side of said plate extending transversely thereof, the mouths of said funnels being adjacent the forward edge of the plate and the discharge ends of the funnels being adjacent and spaced from the central portion of the plate, and a wall extending longitudinally of the plate a short distance in advance of said discharge ends.

11. An air-craft propeller comprising a head adapted for connection to a propeller shaft and a plurality of wings spaced apart circumferentially of the head, each wing comprising an oblong base plate extending laterally from said head and having its rear portion inclining downwardly, and funnels on the upper side of said plate extending transversely thereof, the mouths of said funnels being adjacent the forward edge of the plate and the discharge ends of the funnels being adjacent and spaced from the central portion of the plate.

12. An air-craft propeller comprising a head adapted for connection to a propeller shaft and a plurality of wings spaced apart circumferen tially of the head, each wing comprising an oblong base plate extending laterally from said head and having its rear portion inclining downwardly, funnels on the upper side of said plate extending transversely thereof, the mouths of said funnels being adjacent the forward edge of the plate and the discharge ends of the funnels being adjacent and spaced from the central portion of the plate, and a wall extending longitudinally of the plate a short distance in advance of said discharge ends.

13. An air-craft propeller comprising a head adapted for connection'to a propeller shaft and a plurality of wings spaced apart circumferentially of the head, each wing comprising an oblong base plate extending laterally from said head, funnels on the upper side of the plate having their larger ends facing the direction of motion of the wing and their smaller ends ar-' ranged to discharge air rearwardly above the rear portion of the plate, and a plate at the outer end of the wing projecting upwardly from the base plate and extending to the rear edge thereof.

14. An air-craft propeller comprising a head adapted for connection to a propeller shaft and a plurality of wings spaced apart circumferentially of the head, each, wing comprising an oblong base plate extending laterally from said head, funnels on the upper side of the plate having their larger ends facing the direction of motion of the wing and their smaller ends arranged to discharge air rearwardly above the rear portion of the plate, and a plate at the outer end of the wing projecting upwardly from the base plate and inclining outwardly thereon to the rear edge of the plate.

15. An air-craft propeller comprising a head adapted for connection to a propeller shaft and a plurality of wings spaced apart circumferentially of the head, each wing comprising an oblong base plate extending laterally from said head, funnels on the upper side of the plate having their larger ends facing the direction of motion of the wing and their smaller ends arranged to discharge air rearwardly above the rear portion of the plate, a wall between the plate and funnels, located a'short distance in advance of their discharge ends, forming a pocket between the funnels and plate, and a plate at the outer end of the wing projecting upwardly from the base plate and extending to the rear edge thereof.

16. An air-craft propeller comprising a head adapted for connection to a propeller shaft and a plurality of wings spaced apart circumferentially of the head, each wing comprising an oblong base plate extending laterally from said head and having its rear portion inclining downwardly, funnels on the upper side of said plate extending transversely thereof, the mouths of said funnels being adjacent the forward edge of the plate and the discharge ends of the funnels being adjacent and spaced from the central portion of the plate,

and a wall extending longitudinally of the plate.

and their smaller ends arranged to discharge air rearwardly'above'the rear portion of the plate,

the side walls of said funnels being substantiallyconcentric withthe axis of the head, and a wall between the plate and funnels, located a short distance in advance of their discharge ends, forming a pocket between the funnels and plate.

WILLIAM BRADFORD, JR. 

